Added letter color treshold setting

app/src/main/java/eu/faircode/email/FragmentOptions.java

@@ -40,7 +40,7 @@ public class FragmentOptions extends FragmentBase {
     static String[] OPTIONS_RESTART = new String[]{
             "subscriptions",
             "startup", "cards", "date", "threading", "indentation", "highlight_unread",
-            "avatars", "generated_icons", "identicons", "circular", "saturation", "brightness",
+            "avatars", "generated_icons", "identicons", "circular", "saturation", "brightness", "threshold",
             "name_email", "distinguish_contacts", "authentication",
             "subject_top", "subject_italic", "subject_ellipsize",
             "flags", "flags_background", "preview", "preview_italic",

app/src/main/java/eu/faircode/email/FragmentOptionsDisplay.java

@@ -63,6 +63,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
     private ImageView ivBlue;
     private SeekBar sbSaturation;
     private SeekBar sbBrightness;
+    private SeekBar sbThreshold;
     private SwitchCompat swNameEmail;
     private SwitchCompat swDistinguishContacts;
     private SwitchCompat swAuthentication;
@@ -86,7 +87,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
 
     private final static String[] RESET_OPTIONS = new String[]{
             "theme", "startup", "cards", "date", "threading", "indentation", "highlight_unread",
-            "avatars", "generated_icons", "identicons", "circular", "saturation", "brightness",
+            "avatars", "generated_icons", "identicons", "circular", "saturation", "brightness", "threshold",
             "name_email", "distinguish_contacts", "authentication",
             "subject_top", "subject_italic", "subject_ellipsize",
             "flags", "flags_background", "preview", "preview_italic", "addresses", "attachments_alt",
@@ -120,6 +121,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
         ivBlue = view.findViewById(R.id.ivBlue);
         sbSaturation = view.findViewById(R.id.sbSaturation);
         sbBrightness = view.findViewById(R.id.sbBrightness);
+        sbThreshold = view.findViewById(R.id.sbThreshold);
         swNameEmail = view.findViewById(R.id.swNameEmail);
         swDistinguishContacts = view.findViewById(R.id.swDistinguishContacts);
         swAuthentication = view.findViewById(R.id.swAuthentication);
@@ -217,6 +219,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
                 swIdenticons.setEnabled(checked);
                 sbSaturation.setEnabled(swGeneratedIcons.isChecked());
                 sbBrightness.setEnabled(swGeneratedIcons.isChecked());
+                sbThreshold.setEnabled(swGeneratedIcons.isChecked());
                 ContactInfo.clearCache();
             }
         });
@@ -276,6 +279,25 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
             }
         });
 
+        sbThreshold.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
+            @Override
+            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
+                prefs.edit().putInt("threshold", progress).apply();
+                updateColor();
+                ContactInfo.clearCache();
+            }
+
+            @Override
+            public void onStartTrackingTouch(SeekBar seekBar) {
+                // Do nothing
+            }
+
+            @Override
+            public void onStopTrackingTouch(SeekBar seekBar) {
+                // Do nothing
+            }
+        });
+
         swNameEmail.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -482,10 +504,14 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
         swIdenticons.setChecked(prefs.getBoolean("identicons", false));
         swIdenticons.setEnabled(swGeneratedIcons.isChecked());
         swCircular.setChecked(prefs.getBoolean("circular", true));
+
         sbSaturation.setProgress(prefs.getInt("saturation", 100));
         sbSaturation.setEnabled(swGeneratedIcons.isChecked());
         sbBrightness.setProgress(prefs.getInt("brightness", 100));
         sbBrightness.setEnabled(swGeneratedIcons.isChecked());
+        sbThreshold.setProgress(prefs.getInt("threshold", 50));
+        sbThreshold.setEnabled(swGeneratedIcons.isChecked());
+
         swNameEmail.setChecked(prefs.getBoolean("name_email", false));
         swDistinguishContacts.setChecked(prefs.getBoolean("distinguish_contacts", false));
         swAuthentication.setChecked(prefs.getBoolean("authentication", true));

app/src/main/java/eu/faircode/email/ImageHelper.java

@@ -124,6 +124,7 @@ class ImageHelper {
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
         float s = prefs.getInt("saturation", 100) / 100f;
         float v = prefs.getInt("brightness", 100) / 100f;
+        float t = prefs.getInt("threshold", 50) / 100f;
 
         int bg = Color.HSVToColor(new float[]{h, s, v});
         double lum = ColorUtils.calculateLuminance(bg);
@@ -133,7 +134,7 @@ class ImageHelper {
         canvas.drawColor(bg);
 
         Paint paint = new Paint();
-        paint.setColor(lum < 0.5 ? Color.WHITE : Color.BLACK);
+        paint.setColor(lum < t ? Color.WHITE : Color.BLACK);
         paint.setTextSize(size / 2f);
         paint.setTypeface(Typeface.DEFAULT_BOLD);
 

app/src/main/res/layout/fragment_options_display.xml

@@ -235,7 +235,7 @@
             android:layout_height="wrap_content"
             android:max="100"
             android:min="0"
-            android:progress="50"
+            android:progress="100"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/tvSaturation" />
@@ -258,11 +258,34 @@
             android:layout_height="wrap_content"
             android:max="100"
             android:min="0"
-            android:progress="50"
+            android:progress="100"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/tvBrightness" />
 
+        <TextView
+            android:id="@+id/tvThreshold"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="12dp"
+            android:layout_marginEnd="48dp"
+            android:text="@string/title_advanced_color_threshold"
+            android:textAppearance="@style/TextAppearance.AppCompat.Small"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/sbBrightness" />
+
+        <SeekBar
+            android:id="@+id/sbThreshold"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:max="100"
+            android:min="0"
+            android:progress="50"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/tvThreshold" />
+
         <androidx.appcompat.widget.SwitchCompat
             android:id="@+id/swNameEmail"
             android:layout_width="0dp"
@@ -271,7 +294,7 @@
             android:text="@string/title_advanced_name_email"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toBottomOf="@id/sbBrightness"
+            app:layout_constraintTop_toBottomOf="@id/sbThreshold"
             app:switchPadding="12dp" />
 
         <TextView

app/src/main/res/values/strings.xml

@@ -252,6 +252,7 @@
     <string name="title_advanced_circular">Show round icons</string>
     <string name="title_advanced_color_saturation">Saturation</string>
     <string name="title_advanced_color_value">Brightness</string>
+    <string name="title_advanced_color_threshold">Threshold letter color</string>
     <string name="title_advanced_name_email">Show names and email addresses</string>
     <string name="title_advanced_authentication">Show a warning when the receiving server could not authenticate the message</string>
     <string name="title_advanced_subject_top">Show subject above sender</string>